Compilare: main.c: In function 'main': main.c:10:22: warning: operation on 'a' may be undefined [-Wsequence-point] while (b) b ^= a ^= b ^= a %= b; ^~ main.c:10:17: warning: operation on 'b' may be undefined [-Wsequence-point] while (b) b ^= a ^= b ^= a %= b; ^~ main.c:9:5: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d%d",&a,&b); ^~~~~~~~~~~~~~~~~~~~~~~